Sales at the FTSE 250 company came in ahead of expectations, rising 2.4pc to £1.84bn, as customers were offered sweeteners such as a free TV upgrade in the wake of the hack.

So far this year, TalkTalk has recorded its highest-ever levels of customer loyalty as measured by “churn” – the rate at which customers are leaving.

However, despite a low 1.3pc churn rate, the hack attack alone cost TalkTalk 95,000 customers over the year, meaning that in the 12 months to April, TalkTalk added just 4,000 customers to its phone and broadband service.

The telecoms group has now changed its strategy from undercutting rivals on price to improving its customer service, spending £19m over the period on an IT project to improve service and prevent billing errors.

Ms Harding said: “Our greater focus on customers has been a success, and we are seeing growing benefits from our simplification programme.”